Half of the magnesium in your body is found in your bones, while most of the other half is located inside your cells. A small percentage circulates throughout the bloodstream. Magnesium aids in hundreds of chemical reactions, ensures that nerves and muscles function properly, maintains regular heart beat and helps your bones stay healthy. If magnesium levels in the body become too high or too low, it can cause disruptions in these processes.
A magnesium deficiency occurs when magnesium stored in the body becomes depleted due to chronic insufficient intake of magnesium. Magnesium is absorbed through the intestines, where it travels through the bloodstream to your cells and tissues. Because magnesium is absorbed in the intestines, magnesium deficiency often occurs as a result of gastrointestinal disorders, such as Crohn's disease and ulcerative colitis, which affect proper absorption. Chronic diarrhea or vomiting can also cause magnesium deficiency. When a magnesium deficiency initially develops, it can cause loss of appetite, nausea, vomiting, weakness and fatigue. As the deficiency progresses, it can result in muscle spasms, muscle cramps, tingling, numbness and abnormal heart rhythms. Some people may even experience seizures.
Magnesium toxicity develops when there is too much magnesium in the body. "Nutrition and You" notes that magnesium toxicity does not occur from excess consumption of foods that contain magnesium, but rather from consuming large amounts of magnesium through supplements. Those with kidney damage of failure are at an increased risk of developing magnesium toxicity. When magnesium toxicity occurs, it causes various gastrointestinal symptoms, including diarrhea, abdominal cramps and nausea. As magnesium levels increase, it can result in confusion, loss of appetite, difficulty breathing and low blood pressure.
The Food and Nutrition Board, which is a subgroup of the Institute of Medicine, has determined a recommended daily intake of magnesium to help prevent the development of a magnesium deficiency. Recommendations are classified based on age and sex. Males between the ages of 14 and 18 should consume 410 mg of magnesium per day, whereas females of the same age should consume 360 mg per day. Adult men between 19 and 30 should aim for 400 mg of magnesium per day, and adult women of the same age should consume 310 mg. Adult men over the age of 30 should consume 420 mg per day and adult women over the age of 30 should consume 320 mg daily.
An upper tolerable intake level has been set for magnesium supplements. The upper tolerable intake level defines the highest amount of supplemental magnesium you can consume per day without adverse side effects. This level has been set at 350 mg for men and women.
Food Sources of Magnesium
"Nutrition and You" states that Americans receive most of their dietary magnesium through vegetables, whole grains, nuts and fruits. Other good sources of magnesium include milk, yogurt, meat and eggs.
Some people, such as pregnant women or those who abuse alcohol, may have increased magnesium needs. It may be beneficial to work closely with your doctor or a dietitian to determine your specific magnesium needs.